MCB then RCD

[peeko]

Hi everyone, hope you can help

Recently we've completed an EICR on a commercial property and it's thrown up some issues with the lighting. The installation method is rough as, T&E just chucked on top of the ceiling tiles as we've all seen a million times before so we'll be sorting this as part of the remedial works.

One of the issues I have is that I'm not convinced from looking at the state of it is that the cables in the walls/partitions of the office areas have the adequate 50mm protection/are inside metal conduit, therefore as per amendment 3 I've got to provide RCD protection to the circuit.

The circuits come off an old Square D 3 phase DB, and if anyone has had the misfortune to look for RCBO's that fit these, they'll tell you they're hard to get hold of and cost a small fortune. My idea is this - adequately protected cable from the current MCB to a separate enclosure of double pole RCD's, which then provide protection to each lighting circuit.

I've been told this is OK, just wondered if anybody has experience of this, pro's/con's etc? Obviously in an ideal world I'd swap the board for something more modern with RCBO's that are available/not a fortune, but for a couple of circuits I don't think they'd go with the cost of this, maybe down the line as they make alterations.

Thanks in advance
Charlie

 

[hightower]

Sounds like a plan to me, people often do this in domestic for new shower circuits etc.

Only thing I'd say about it is make it bloody obvious that there's a protection device after the MCB - if somebody on site needs to reset it, they may not know it's related if it's not obvious to them.

P.S. Isn't this a bit above the remit of a PAT Tester?

 

[Deleted member 72666]

How old is the installation?

 

[Andy78]

Have you tried Schneider for a compatible rcbo ?

 

[peeko]

very much above the remit of a PAT tester!

Won't be attempting myself - our sparks will be installing/testing/cert-ing, just like to make sure they're not bull****ing me at times, especially when it's a scenario I've not seen before.

Installation is about 35-40 yrs old

 

[peeko]

Hi Andy, they sent me 2 part codes - however every site I check says they're discontinued, not keen on putting used in off fleabay

 

[Deleted member 72666]

"One of the issues I have is that I'm not convinced from looking at the state of it is that the cables in the walls/partitions of the office areas have the adequate 50mm protection/are inside metal conduit, therefore as per amendment 3 I've got to provide RCD protection to the circuit"


Has the client requested the code 3 work?

 

[peeko]

Hi Stan - yes 2 quotes, one C2s, one for C3s. Last time we did work there they did all.

 

[Andy78]

Hi Andy, they sent me 2 part codes - however every site I check says they're discontinued, not keen on putting used in off fleabay

I would persist with that one. Last schneider rcbos I used in a square d tpn board was only a couple of years ago.

 

[peeko]

Thanks Andy, I'll have another look, might be a case of ringing round to see if anyone has any surplus stock gathering dust

 

[Jay Sparks]

Thanks Andy, I'll have another look, might be a case of ringing round to see if anyone has any surplus stock gathering dust

You could even ask about on here. Start a thread and see if any members have any kicking about, like you say, gathering dust. Not sure what part of the forum you would be best putting in though.

Jay

 

[Andy78]

Thanks Andy, I'll have another look, might be a case of ringing round to see if anyone has any surplus stock gathering dust

What series are the old Square D and what serial numbers have schneider provided you with ?

 

[westward10]

Schneider rcbos are readily available for Square D KQ boards. I am not so sure, if it is a QOE board that they are compatible but I could be wrong.

 

[Sam cook]

I've just recently fitted Schneider KQE RCbo Devices In a square d push fit bus bar 3 phase Board. Funny really about five years ago I sold a load of square d rcbos becaue couldn't see me using them and already go ample stock of MCB and rcbo devices. My wholesaler holds them for me. Some say ironic at what the Schneider cost in region of 50-60 quid.